How to add a second server to my ispconfig?

Dear guys
Due to my previous problem with port changing for smtp service I found a solution to use 2 servers parallel together one for sending and one for receiving in order to enable me blocking port 25 on my smtp server. so here are my questions:
1- I have already configed my first server with ispconfig. now is it possible to add a second server to my ispconfig system without loosing my previous data and settings and configurations on first server (Just adding a second server without harming the first one). if yes how am I suppose to do that?
is there a tutorial or something?
2- how do I config my ispconfig to define that all receiving emails come to first server and all outgoing emails , be sent from the second server in ispconfig
3- Can I use the second server both for smtp service and a backup of my data on first server using rsync or something like that